Just been looking at this myself, but there seem to be three different ways to fit a straight steerer fork into a tapered headtube.
Steerer adapter like Hope HS136 (like this : http://www.merlincycles.com/bike-shop/mtb-parts/mtb-accessories/headsets-1/hope-hs136-15-1-1-8-reducer.html )
– I guess that this allows the crown race from the tapered headset to be fitted to a straight steerer, and only adds a few mm to the stack height.
Reducer crown race (like this http://www.jensonusa.com/FSA-Integrated-Crown-Race-Reducer )
– I guess that this directly replaces the crown race that comes with the original tapered headset. Others are available from Nukeproof and so on BUT no-one seem to specify the angles or exact dimensions of the race surface, so there’s a chance that they won’t match up even if it’s the correct brand?
Reducer headset – fits into a tapered headtube but has inner dimensions for a straight steerer. Might be tricky finding the right one, given the bewildering array of standards, types and sizes.
I suppose that the best thing to use is a reducer headset (if you can find on to fit the frame, followed by a steerer adapter if you’ve got the original crown race, followed by a reducer race if you can find one to fit the lower bearing. Is that about right, anyone??
